private function getCacheDir($user, $imageIdentifier)
{
$userPath = str_pad($user, 3, '0', STR_PAD_LEFT);
return sprintf('%s/%s/%s/%s/%s/%s/%s/%s/%s', $this->path, $userPath[0], $userPath[1], $userPath[2], $user, $imageIdentifier[0], $imageIdentifier[1], $imageIdentifier[2], $imageIdentifier);
}